XOMA Nominates Former FDA Chief Counsel Peter Barton Hutt to Board of

    Business Editors/Health/Medical Writers
    BIOWIRE2K

    BERKELEY, Calif.--(BUSINESS WIRE)--Feb. 28, 2005---XOMA Ltd. (Nasdaq:XOMA) today announced that Peter Barton Hutt, former chief counsel for the Food and Drug Administration (FDA), has been nominated to become a member of its board of directors. Mr. Hutt has agreed to serve if elected by shareholders at XOMA's annual meeting scheduled for May 19, 2005. Steven C. Mendell, XOMA's former chief executive and a board member since 1984, has decided not to stand for re-election.
    Mr. Hutt is currently senior counsel to the Washington, D.C. law firm of Covington & Burling, specializing in food and drug law and trade association law. From 1971 to 1975 Hutt was chief counsel for the Food and Drug Administration. Since 1994 he has taught a full course on food and drug Law at Harvard Law School and taught the same course at Stanford Law School in 1998. He is also a co-author of Food and Drug Law: Cases and Materials.
    "Peter will be a great addition to our board of directors," said John L. Castello, president, chairman and chief executive officer of XOMA. "We look forward to tapping his extensive knowledge gained in over three decades of experience in the healthcare and pharmaceutical industries as well as the unique perspective he will bring in helping XOMA drive its drug development strategy."
    "We are grateful to Steve for his many contributions to XOMA over the years as an executive and board member, and are sorry that his current heavy work and travel schedule doesn't permit him to continue on our board," added Castello.
    Mr. Hutt serves on a wide variety of academic and advisory boards, including the Institute of Medicine (IOM) of the National Academy of Sciences (NAS) and the Panel on the Administrative Restructuring of the National Institutes of Health (NIH). Additionally, he serves as Legal Counsel to the Society of Risk Analysis as well as the American College of Toxicology.
    Formerly, he has served on the IOM Executive Committee, Advisory Committee to the Director of the NIH, the NAS Committee on Research Training in the Biomedical and Behavioral Sciences, and the National Committee to Review Current Procedures for Approval of New Drugs for Cancer and AIDS established by the President's Cancer Panel of the National Cancer Institute at the request of President George Bush.
    Mr. Hutt received his undergraduate degree from Yale University, and law degrees from Harvard University and New York University.

    About XOMA

    XOMA develops and commercializes antibody and other protein-based biopharmaceuticals for cancer, immune disorders and infectious diseases. The company pipeline includes products from collaborative product development programs with Chiron Corporation, Millennium Pharmaceuticals, Inc., Aphton Corporation and Alexion Pharmaceuticals, Inc. For more information about XOMA's product pipeline and antibody product development capabilities and technologies, please visit XOMA's website at http://www.xoma.com/.

    Certain statements contained herein concerning current collaborations and product development or that otherwise relate to future periods, are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to certain risks inherent in the biotechnology industry and for companies engaged in the development of new products in a regulated market. These risks, including those related to the results of pre-clinical testing, the timing or results of pending and future clinical trials (including the design and progress of clinical trials; safety and efficacy of the products being tested; action, inaction or delay by the FDA, European or other regulators or their advisory bodies; and analysis or interpretation by, or submission to, these entities or others of scientific data), changes in the status of the existing collaborative relationships, the ability of collaborators and other partners to meet their obligations, market demand for products, scale up and marketing capabilities, competition, uncertainties regarding the status of biotechnology patents, uncertainties as to the cost of protecting intellectual property and risks associated with XOMA's status as a Bermuda company, are described in more detail in the Company's most recent annual report on Form 10-K and in other SEC filings.

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CONTACT: XOMA Ltd. Deb McManus, 510-204-7240 (Media Relations) or Kureczka/Martin Associates Ellen M. Martin, 510-832-2044 (Investor Relations)

KEYWORD: CALIFORNIA INDUSTRY KEYWORD: GOVERNMENT PHARMACEUTICAL MEDICAL BIOTECHNOLOGY MANAGEMENT CHANGES SOURCE: XOMA Ltd.

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